Monaco editor doesn't always updated live snippet

## Description of the issue

Sometimes the monaco editor panels don't have the latest data when you run a snippet.

## Steps to reproduce

1. start a new jsgist
2. in the HTML panel type `<h1>foo</h1>`
3. click run
4. in the HTML panel erase the code
5. click run

## What should happen:

The run window is empty

## What happens instead

The run window shows `foo`